Structural control for inhibiting SO2 adsorption in porous MnCe nanowire aerogel catalysts for low-temperature NH3-SCR

Wang, Chengzhi; Gao, Feifei; Ko, Songjin; Liu, Hengheng; Yi, Honghong; Tang, Xiaolong

doi:10.1016/j.cej.2022.134729

Cited by 47 publications

(14 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because oxygen vacancies were very active and could be combined with other atoms, oxygen vacancies could be present as surface-adsorbed oxygen species. 40 In addition, oxygen vacancies always exist on the surface of catalysts prepared under an inert atmosphere. 41 Considering the results of XRD and H 2 -TPR, it was believed that more oxygen vacancies formed in Fe 9 CeO x -N 2 , resulting in more surface-adsorbed oxygen species.…”

Section: Resultsmentioning

confidence: 99%

Promoting effect ofN₂calcination onFeCeO_xfor selective catalytic reduction ofNO_xwithNH₃

Xie

Ren

et al. 2023

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

BACKGROUNDSelective catalytic reduction of NOx with NH3 (NH3‐SCR) technology is effective for NOx removal. Acidity and redox ability are two significant characteristics for NH3‐SCR catalysts. This study investigated the effects of N2 calcination on the NH3‐SCR performance of FeCeOx, inspired by the promotion of active oxygen species with inert atmosphere calcination. The structure‐activity relationship and reaction mechanism of the two catalysts (Fe9CeOx‐N2 and Fe9CeOx‐air) were concluded based on the results of characterization.RESULTSFe9CeOx‐N2 showed better NOx conversion and SO2 resistance than Fe9CeOx‐air, especially in low and medium temperature range. For fresh catalysts, a higher amount of Oα, Fe3+ and Ce3+ promoted the redox ability of Fe9CeOx‐N2, and further improved the NOx adsorption and activation. Additionally, the greater number of acid sites of Fe9CeOx‐N2 was another reason for its competitive performance. For SO2‐poisoned catalysts, the primary reaction pathway was the reaction between pre‐adsorbed NH3 species and NOx. The higher amount of acidity from metal sulfate contributed to its better SO2 tolerance of Fe9CeOx‐N2.CONCLUSIONHigher redox ability and acidity led to better NH3‐SCR activity and SO2 tolerance of Fe9CeOx‐N2. This study provides a feasible preparation method for enhancing the NOx conversion and SO2 tolerance of NH3‐SCR catalysts. © 2023 Society of Chemical Industry.

show abstract

Section: Resultsmentioning

confidence: 99%

Promoting effect ofN₂calcination onFeCeO_xfor selective catalytic reduction ofNO_xwithNH₃

Xie

Ren

et al. 2023

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

show abstract

“…The reaction between NO 2 and adsorbed NH 3 or NH 4 + is important in promoting the low-temperature activity of the SCR system. Wang et al found that for Mn-P, Mn-N, and MnCe-N catalysts, the order for SCR activities of the catalysts was consistent with their ability to catalyze oxidation of NO to NO 2 , so oxidation of NO to NO 2 was thought to be important for the excellent catalytic activity of the MnCe-N catalyst. Ni et al .…”

Section: Design Guidelines For Efficient Low-temperature Scr Catalystsmentioning

confidence: 97%

“…Due to the synergistic effect of Mn and Ce, Mn-CeO x /NF provided over 85% NO conversion at 150−225 °C. Wang et al 96 designed a layered porous nanowire-structured catalyst (MnCe-N) by in situ self-assembly, and it exhibited over 90% NO x conversion at 100−400 °C. In addition, the NO x conversion efficiency of the MnCe-N catalyst was barely inhibited by SO 2 (250 ppm).…”

Section: Metal Oxide Catalysts 321 V 2 O 5 -Based Catalystsmentioning

confidence: 99%

Toward an Atomic-Level Understanding of the Catalytic Mechanism of Selective Catalytic Reduction of NO_x with NH₃

2022

View full text Add to dashboard Cite

As primary air pollutants, nitrogen oxides (NO x ) result in a series of environmental issues, such as photochemical smog, acid rain, ozone depletion, and fine particle pollution, which threaten the health of all human beings. Selective catalytic reduction with NH 3 (NH 3 -SCR) is the most powerful technique for the abatement of NO x . The development of NH 3 -SCR catalysts is the key to the normal operation of NO x removal systems. The currently used V 2 O 5 -WO 3 (MoO 3 )/TiO 2 catalysts are widely applicable for medium-/high-temperature conditions but are not suitable for NH 3 -SCR operated at low temperatures. The development of high-efficiency low-temperature SCR catalysts is the central issue at present. The rational design of efficient NH 3 -SCR catalysts requires an atomic-level understanding of their mode of operation, including the identification and characterization of the active sites, reaction paths, and rate-determining steps of NH 3 -SCR. Herein, we summarize the recent advances in catalysts for low-temperature NH 3 -SCR. The active sites, intermediates, and reaction pathways of oxide catalysts and molecular sieve catalysts mainly studied by researchers will be reviewed, with a particular focus on an atomic-level understanding of the mechanism. We provide an atomic-level understanding of the current general NH 3 -SCR catalytic mechanism and further combine the atomic-level understanding of the mechanism to provide design guidelines for low-temperature SCR catalysts. We hope that our account will trigger research activities and discussions in NH 3 -SCR catalysis and bridge the material gap between idealized and real catalytic systems.

show abstract

“…Previous studies have reported that the formed Ce 3+ species could act as an inducement for the generation of unsaturated chemical bonds and vacancies on the catalyst surface, leading to more hydroxyl-like groups or surface oxide defects. 51,52 After 1 wt % K 2 O poisoning, the Ce 3+ ratio of the Ti/Ce catalyst descended from 13.43 to 11.15%, which might be owing to K hindering the electron transfer between Ce and Ti. 53,54 With regard to the TiCu/Ce catalyst, the Ce 3+ content exhibited a quite slight decrease from 15.89 to 15.05% after the K poisoning.…”

Section: Surface Acidic Propertiesmentioning

confidence: 99%

Improved K-Resistance of a Cu-Modified TiO₂/CeO₂ Catalyst for SCR of NO_x at Low Temperatures

Zhao

et al. 2023

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

The employment of CeTi-based catalysts in the denitration of exhaust from biomass combustion is significantly limited by the poor tolerance to alkali metals. Herein, a CuO modification strategy was proposed to enhance the resistance of CeTi catalysts to K2O. The NO conversion of pristine Ti/Ce decreased from 95% to less than 10% at 250 °C after 1 wt % K loading. As a sharp comparison, CuO-modified Ti/Ce reserved more than 70% in NO conversion under the same test conditions. Combined with diverse characterizations, it was found that the addition of CuO promoted the formation of Cu–O–Ce and Cu–O–Ti species, which showed enhanced redox and acid properties. CuO modification also suppressed the adsorption of inert nitrates resulting from K loading. Moreover, Brønsted acid sites introduced by CuO served as capture sites of alkali metals, thus alleviating the active sites from being poisoned. More retained acidic and redox capacities ensured the excellent catalytic performance of TiCu/Ce under K poisoning.

show abstract

Structural control for inhibiting SO2 adsorption in porous MnCe nanowire aerogel catalysts for low-temperature NH3-SCR

Cited by 47 publications

References 61 publications

Promoting effect ofN₂calcination onFeCeO_xfor selective catalytic reduction ofNO_xwithNH₃

Promoting effect ofN₂calcination onFeCeO_xfor selective catalytic reduction ofNO_xwithNH₃

Toward an Atomic-Level Understanding of the Catalytic Mechanism of Selective Catalytic Reduction of NO_x with NH₃

Improved K-Resistance of a Cu-Modified TiO₂/CeO₂ Catalyst for SCR of NO_x at Low Temperatures

Contact Info

Product

Resources

About

Structural control for inhibiting SO2 adsorption in porous MnCe nanowire aerogel catalysts for low-temperature NH3-SCR

Cited by 47 publications

References 61 publications

Promoting effect ofN2calcination onFeCeOxfor selective catalytic reduction ofNOxwithNH3

Promoting effect ofN2calcination onFeCeOxfor selective catalytic reduction ofNOxwithNH3

Toward an Atomic-Level Understanding of the Catalytic Mechanism of Selective Catalytic Reduction of NOx with NH3

Improved K-Resistance of a Cu-Modified TiO2/CeO2 Catalyst for SCR of NOx at Low Temperatures

Contact Info

Product

Resources

About

Promoting effect ofN₂calcination onFeCeO_xfor selective catalytic reduction ofNO_xwithNH₃

Promoting effect ofN₂calcination onFeCeO_xfor selective catalytic reduction ofNO_xwithNH₃

Toward an Atomic-Level Understanding of the Catalytic Mechanism of Selective Catalytic Reduction of NO_x with NH₃

Improved K-Resistance of a Cu-Modified TiO₂/CeO₂ Catalyst for SCR of NO_x at Low Temperatures